how to write Jquery Ajax and Josn in Asp.Net Web Form?

Question

<script type="text/javascript">    
$(document).ready(function () {       
$.ajax({           
type: "POST",       
contentType: "application/json; charset=utf-8",
url: "Bind/BindDatatable",         
data: "{}",          
dataType: "json",      
success: function (data) {    
for (var i = 0; i < data.d.length; i++) {            
$("#gvDetails").append("<tr><td>" + data.d[i].UserId + "</td><td>" + data.d[i].UserName + "</td><td>"
 + data.d[i].Location + "</td></tr>"); 
}          
},      
error: function (result) {      
alert("Error");      
}    
});  
});
</script>

After Page Loading Error will came ...plz help me...

Hide Copy Code

url: "Bind/BindDatatable",

------>how to write this line code
iam using web forms....